scholarly journals Conformationally active integrin endocytosis and traffic: why, where, when and how?

2020 ◽  
Vol 48 (1) ◽  
pp. 83-93 ◽  
Author(s):  
Giulia Mana ◽  
Donatella Valdembri ◽  
Guido Serini
Keyword(s):  
Dynamic Equilibrium ◽  
Cell Metabolism ◽  
Active Conformation ◽  
Proteolytic Fragment ◽  
The Past ◽  
Adhesion Sites ◽  
Ecm Proteins ◽  
Polarized Secretion ◽  
Multicellular Organisms ◽  
Spatiotemporal Control

Spatiotemporal control of integrin-mediated cell adhesion to the extracellular matrix (ECM) is critical for physiological and pathological events in multicellular organisms, such as embryonic development, angiogenesis, platelet aggregation, leukocytes extravasation, and cancer cell metastatic dissemination. Regulation of integrin adhesive function and signaling relies on the modulation of both conformation and traffic. Indeed, integrins exist in a dynamic equilibrium between a bent/closed (inactive) and an extended/open (active) conformation, respectively endowed with low and high affinity for ECM ligands. Increasing evidence proves that, differently to what hypothesized in the past, detachment from the ECM and conformational inactivation are not mandatory for integrin to get endocytosed and trafficked. Specific transmembrane and cytosolic proteins involved in the control of ECM proteolytic fragment-bound active integrin internalization and recycling exist. In the complex masterplan that governs cell behavior, active integrin traffic is key to the turnover of ECM polymers and adhesion sites, the polarized secretion of endogenous ECM proteins and modifying enzymes, the propagation of motility and survival endosomal signals, and the control of cell metabolism.

scholarly journals Mutation and the evolution of ageing: from biometrics to system genetics

2010 ◽  
Vol 365 (1544) ◽  
pp. 1273-1279 ◽  
Author(s):  
Kimberly A. Hughes
Keyword(s):  
Evolutionary Genetics ◽  
Genetic Networks ◽  
Past Century ◽  
The Past ◽  
Laboratory Populations ◽  
Empirical Tests ◽  
Genetics And Genomics ◽  
Multicellular Organisms ◽  
Modern Population ◽  
Quantitative Explanation

A notable success for evolutionary genetics during the past century was to generate a coherent, quantitative explanation for an apparent evolutionary paradox: the tendency for multicellular organisms to show declining fitness with age (senescence, often referred to simply as ‘ageing’). This general theory is now widely accepted and explains most of the features of senescence that are observed in natural and laboratory populations, but specific instantiations of that theory have been more controversial. To date, most of the empirical tests of these models have relied on data generated from biometric experiments. Modern population genetics and genomics provide new, and probably more powerful, ways to test ideas that are still controversial more than half a century after the original theory was developed. System-genetic experiments have the potential to address both evolutionary and mechanistic questions about ageing by identifying causal loci and the genetic networks with which they interact. Both the biometrical approaches and the newer approaches are reviewed here, with an emphasis on the challenges and limitations that each method faces.

scholarly journals Results of Chernovskoe Reservoir hydro botanical monitoring from 1974 to 2015

2017 ◽  
Vol 6 (1) ◽  
pp. 77-82
Author(s):  
Vera Valentinovna Solovieva
Keyword(s):  
Dynamic Equilibrium ◽  
Floristic Diversity ◽  
Reservoir Water ◽  
Reservoir Water Level ◽  
Important Indicator ◽  
Vegetation Growth ◽  
The Past ◽  
Coastal Plant ◽  
Level Lowering ◽  
Water Vegetation

Features of reservoirs use make it necessary to collect, analyse and synthesise environmental information about the state of hydroecosystems with a purpose of their development forecast. Overgrowing processes are an important indicator of ecosystem. The following paper contains the results of the study of Chernovskoe reservoir flora and vegetation in different years. Floristic diversity is compared with other reservoirs and hydro botanic information about them has already been published in a number of the authors papers. The comparative analysis has shown that the overall composition of reservoirs flora is random, while there is some regularity in the environmental spectrum - each of them is characterized by a small number of aquatic species and by the dominance of coastal plant species. The study of Chernovskoe reservoir vegetation has shown that the composition of dominants has changed over the past 40 years, from 1974 to 2015. There is a dominance of air water vegetation above the water one, but the borders of the water vegetation growth have widened. Chernovskoe reservoir is currently in dynamic equilibrium. The lifetime of aquatic ecosystem at this stage may be unlimited if there is an unstable hydro regime and impulsive character of water use. The reservoir water level lowering may lead to overgrowth and accelerate activation of waterlogging.

Molecular Paleontology and Biochemical Evolution

2008 ◽  
Author(s):  
Susan M. Gaines ◽  
Geoffrey Eglinton ◽  
Jürgen Rullkötter
Keyword(s):  
Twentieth Century ◽  
Cambrian Explosion ◽  
Microbial World ◽  
Form And Function ◽  
The Past ◽  
Unicellular Algae ◽  
Almost All ◽  
And Function ◽  
Multicellular Organisms ◽  
Molecular Paleontology

Carl Woese’s drive for a unified system of biological classification didn’t just open the microbial world to exploration: it reshuffled the entire taxonomic system and revolutionized the way that biologists study evolution, reigniting interest in preanimal evolution. Studies of evolution from the mid-nineteenth through most of the twentieth century relied on the comparison of forms in living and fossil organisms and were limited to the complex multicellular organisms that developed over the past 550 million years. In other words, much was known about the evolution of animals and land plants that left distinctive hard fossils, and very little was known about the unicellular algae and microorganisms that occupied the seas for most of the earth’s history. Woese’s Tree of Life, derived from nucleic acid sequences in ribosomal RNA, has revealed ancestral relationships that form and function don’t even hint at, allowing biologists to look beyond the rise of multicellular life and link it with less differentiated, more primal forms—which was precisely Woese’s intention. But evolution is a history, not just a family tree of relationships. If the information stored in the genes of extant organisms is to provide true insight into that history, it needs to be anchored in time, linked to extinct organisms and to past environments. Ultimately, we must look to the record in the rocks and sediments, just as paleontologists and biologists have been doing for the past two centuries. In Darwin’s time, that record comprised rocks from the past 550 million years, a span of time that geologists now call the Phanerozoic eon, based on Greek words meaning visible or evident life. The eon began with the rocks of the Cambrian period, in which nineteenth- and early-twentieth-century paleontologists discovered a fabulous assortment of fossils—traces of trilobites, anemones, shrimp, and other multicellular animals that were completely missing from any of the earlier strata. Thousands of new animals and plants, including representatives of almost all contemporary groups, as well as hundreds of now-extinct ones, appeared so suddenly between 542 and 530 million years ago that paleontologists refer to the phenomenon as the Cambrian “explosion.”

An equilibrium path for institutional change in China

2016 ◽  
Vol 28 (1) ◽  
pp. 399-414
Author(s):  
Shixiong Cao ◽  
Zhiguang Ren
Keyword(s):  
Economic Development ◽  
Institutional Change ◽  
Political Institutions ◽  
Dynamic Equilibrium ◽  
Institutional Changes ◽  
Equilibrium Path ◽  
New Era ◽  
The Past ◽  
Economic Practices ◽  
New Institutions

China’s economic and political reforms since 1978 represent one of the biggest institutional changes in the last century. Because most research has focused on the economics of institutional change rather than the evolution of political institutions, a theoretical framework to explain China’s rapid economic development is lacking. To understand the successes and failures of China’s institutional change, we reviewed China’s innovative political and economic practices during the past 30 years. We found that the country’s political and economic institutions combine to form a dynamic equilibrium that can explain the impressive economic results. China’s leaders dream of new institutions that will improve upon traditional Western capitalism, based on a combination of central planning with traditional capitalist approaches that increase the system’s flexibility. If China’s leaders can combine this approach with decreased social costs compared with previous socioeconomic systems, this will represent a new era and a model that other nations can follow.

Linking glutamate receptor movements and synapse function

Science ◽  
2020 ◽  
Vol 368 (6496) ◽  
pp. eaay4631 ◽  
Author(s):  
Laurent Groc ◽  
Daniel Choquet
Keyword(s):  
Synaptic Transmission ◽  
Glutamate Receptor ◽  
Dynamic Equilibrium ◽  
Brain Disease ◽  
Receptor Trafficking ◽  
Degradation Pathways ◽  
Neurotransmitter Receptor ◽  
The Past ◽  
New Methods ◽  
Technological Advances

Regulation of neurotransmitter receptor content at synapses is achieved through a dynamic equilibrium between biogenesis and degradation pathways, receptor stabilization at synaptic sites, and receptor trafficking in and out synapses. In the past 20 years, the movements of receptors to and from synapses have emerged as a series of highly regulated processes that mediate postsynaptic plasticity. Our understanding of the properties and roles of receptor movements has benefited from technological advances in receptor labeling and tracking capacities, as well as from new methods to interfere with their movements. Focusing on two key glutamatergic receptors, we review here our latest understanding of the characteristics of receptor movements and their role in tuning the efficacy of synaptic transmission in health and brain disease.

scholarly journals Current Status of Low Intensity Pulsed Ultrasound for Dental Purposes

2012 ◽  
Vol 6 (1) ◽  
pp. 220-225 ◽  
Author(s):  
Emanuel Braga Rego ◽  
Takashi Takata ◽  
Kazuo Tanne ◽  
Eiji Tanaka
Keyword(s):  
Tissue Engineering ◽  
Present Article ◽  
Cell Metabolism ◽  
Periodontal Regeneration ◽  
Current Status ◽  
Biological Functions ◽  
Pulsed Ultrasound ◽  
Low Intensity Pulsed Ultrasound ◽  
Low Intensity ◽  
The Past

Over the past few years, tissue engineering applied to the dental field has achieved relevant results. Tissue engineering can be described by actions taken to improve biological functions. Several methods have been described to enhance cellular performance and low intensity pulsed ultrasound (LIPUS) has shown to play an important role in cell metabolism. The present article provides an overview about the current status of LIPUS as a tissue engineering tool to be used to enhance tooth and periodontal regeneration.

scholarly journals Recent Advances in Photo-Responsive Polypeptide Derived Nano-Assemblies

2018 ◽  
Author(s):  
Lu Yang ◽  
Houliang Tang ◽  
Hao Sun
Keyword(s):  
Value Added ◽  
Polymeric Materials ◽  
Industrial Applications ◽  
Ease Of Use ◽  
Stimuli Responsive ◽  
Future Directions ◽  
Mild Conditions ◽  
The Past ◽  
Current State ◽  
Spatiotemporal Control

Stimuli-responsive polymeric materials have attracted significant attentions in a variety of high-value-added and industrial applications during the past decade. Among various stimuli, light is of particular interest as a stimulus due to its unique advantages such as precisely spatiotemporal control, mild conditions, ease of use, and tunability. In recent years, a lot of effort toward synthesis of biocompatible and biodegradable polypeptide has resulted in many examples of photo-responsive nanoparticles. Depending on the specific photochemistry, those polypeptide derived nano-assemblies are capable of crosslinking, disassembling, or morphing into other shapes upon light irradiation. In this mini-review, we aim to assess the current state of photo-responsive polypeptide based nanomaterials. First, those “smart” nanomaterials will be categorized by their photo-triggered events (i.e., crosslinking, degradation, and isomerization) which are inherently governed by photo-sensitive functionalities including o-nitrobenzyl, coumarin, azobenzene, cinnamyl, and spiropyran. In addition, the properties and applications of those polypeptide nanomaterials will be highlighted as well. Finally, the current challenges and future directions of this subject will be evaluated.

scholarly journals Matrix Valency Regulates Integrin-mediated Lymphoid Adhesion via Syk Kinase

1999 ◽  
Vol 144 (4) ◽  
pp. 777-788 ◽  
Author(s):  
Dwayne G. Stupack ◽  
Erguang Li ◽  
Steve A. Silletti ◽  
Jacqueline A. Kehler ◽  
Robert L. Geahlen ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Cell Adhesion ◽  
Lymphoid Cell ◽  
Lymphoid Cells ◽  
Cooperative Interaction ◽  
Antigen Receptors ◽  
Adhesion Proteins ◽  
Adhesion Sites ◽  
Syk Kinase ◽  
Ecm Proteins

Lymphocytes accumulate within the extracellular matrix (ECM) of tumor, wound, or inflammatory tissues. These tissues are largely comprised of polymerized adhesion proteins such as fibrin and fibronectin or their fragments. Nonactivated lymphoid cells attach preferentially to polymerized ECM proteins yet are unable to attach to monomeric forms or fragments of these proteins without previous activation. This adhesion event depends on the appropriate spacing of integrin adhesion sites. Adhesion of nonactivated lymphoid cells to polymeric ECM components results in activation of the antigen receptor-associated Syk kinase that accumulates in adhesion-promoting podosomes. In fact, activation of Syk by antigen or agonists, as well as expression of an activated Syk mutant in lymphoid cells, facilitates their adhesion to monomeric ECM proteins or their fragments. These results reveal a cooperative interaction between signals emanating from integrins and antigen receptors that can serve to regulate stable lymphoid cell adhesion and retention within a remodeling ECM.

scholarly journals Autophagosome maturation: An epic journey from the ER to lysosomes

2018 ◽  
Vol 218 (3) ◽  
pp. 757-770 ◽  
Author(s):  
Yan G. Zhao ◽  
Hong Zhang
Keyword(s):  
Molecular Mechanisms ◽  
Snare Proteins ◽  
Rab Gtpases ◽  
Lysosomal Storage ◽  
Double Membrane ◽  
Multicellular Organisms ◽  
Autophagosome Maturation ◽  
Spatiotemporal Control ◽  
Autophagy Activity ◽  
Storage Disorders

Macroautophagy involves the sequestration of cytoplasmic contents in a double-membrane autophagosome and their delivery to lysosomes for degradation. In multicellular organisms, nascent autophagosomes fuse with vesicles originating from endolysosomal compartments before forming degradative autolysosomes, a process known as autophagosome maturation. ATG8 family members, tethering factors, Rab GTPases, and SNARE proteins act coordinately to mediate fusion of autophagosomes with endolysosomal vesicles. The machinery mediating autophagosome maturation is under spatiotemporal control and provides regulatory nodes to integrate nutrient availability with autophagy activity. Dysfunction of autophagosome maturation is associated with various human diseases, including neurodegenerative diseases, Vici syndrome, cancer, and lysosomal storage disorders. Understanding the molecular mechanisms underlying autophagosome maturation will provide new insights into the pathogenesis and treatment of these diseases.

scholarly journals The Matrisome during Aging and Longevity: A Systems-Level Approach towards Defining Matreotypes Promoting Healthy Aging

2019 ◽  
Author(s):  
Collin Ewald
Keyword(s):  
Healthy Aging ◽  
Physiological State ◽  
Cell Types ◽  
Physiological Status ◽  
Ecm Proteins ◽  
Age Related ◽  
Accumulation Of Damage ◽  
Cellular Identity ◽  
Multicellular Organisms ◽  
Cellular Components

Accumulation of damage is generally considered the cause of aging. Interventions that delay aging mobilize mechanisms that protect and repair cellular components. Consequently, research has been focused on studying the protective and homeostatic mechanisms within cells. However, in humans and other multicellular organisms, cells are surrounded by extracellular matrices (ECM), which are important for tissue structure, function and intercellular communication. During aging, components of the ECM become damaged through fragmentation, glycation, crosslinking, and accumulation of protein aggregation, all of which contribute to age-related pathologies. Interestingly, placing senescent cells into a young ECM rejuvenates them and we found that many longevity-assurances pathways re-activate de-novosynthesis of ECM proteins during aging. This raises the question of what constitutes a young ECM to reverse aging or maintain health? In order to make inroads to answering this question, I suggest a systems-level approach of quantifying the matrisome or ECM compositions reflecting health, pathology, or phenotype and propose a novel term, the “matreotype”, to describe this. The matreotype is defined as the composition and modification of ECM or matrisome proteins associated with or caused by a phenotype, such as longevity, or a distinct and acute physiological state, as observed during aging or disease. Every cell type produces its unique ECM. Interestingly, cancer-cell types can even be identified based on their unique ECM composition. Thus, the matreotype reflects cellular identity and physiological status. Defined matreotypes could be used as biomarkers or prognostic factors for disease or health status during aging with potential relevance for personalized medicine. Treatment with biologics that alter ECM-to-cell mechanotransduction might be a strategy to reverse age-associated pathologies. An understanding of how to reverse from an old to a young matreotype might point towards novel strategies to rejuvenate cells and help maintain tissue homeostasis to promote health during aging.

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